The IACV is a digital linear actuator (DLA) that accurately controls throttle airflow in an engine system. The need for using an IACV is that pollution emission control regulations require more precise air/fuel ratios in engines so as to produce cleaner emissions. Alternative flow control uses for a DLA are for a fuel cell or Positive Crankcase Ventilation (PCV).
IACVs are being developed for the small engine market such as, for use in two and three-wheeled motorcycles, off-road recreational vehicles, marine outboard motors, portable generators, lawn and garden power tools, etc., to reduce emissions. A throttle valve seat diameter, in the throttle body, for these small engines typically ranges between 3-6 mm. The capnut shape of the IACV determines the airflow profile in the throttle body. For an IACV with 8.5 mm linear travel, the capnut becomes very needle-like in shape. Such needle-like capnut is weak and subject to handling damage before final assembly into the throttle body, which may occur after cross-continent travel.
Thus, there is a need to provide a shroud for protecting the capnut of an IACV for use in a small engine, with the shroud also defining the valve seat.